4th June Night:

Uncertainty remains over the formation and track of the first low pressure system of Arabian Sea (AS-1)!

A cyclonic circulation is seen in mid-levels over southern Arabian Sea. 

This 👆can descend down to form a surface low pressure area by 6th June. 

Below graphic shows the approximate likely scenario as per Vagaries on today's estimate

• AS-1 can form in the yellow circle region.
• Initial track can be between the red lines as it intensifies moving north/northwest. 
• Pink arrows show the forecasted wind flow - as mentioned earlier, break-away winds from AS-1 can reach Kerala to bring in a weak onset of Southwest Monsoon by 6th -8th June.

Mumbai region: Some showers likely in patches during early morning hours of 5th and 6th June. 

Pre-monsoon thundershowers maybe possible after 7th June. 

FAQ Clarification:

As of now, it seems like the Arabian Sea system may not impact Mumbai and Konkan coast and can delay the advance of monsoon along west coast as it can remain far away from coast in the open waters. 

More updates on this as things evolve...